Pole Propelled Velocipede

ABSTRACT

A two wheeled tandem vehicle is propelled by hand-grasped poles. A forward wheel on a forward member and a rear wheel on a rearward member align along a longitudinal axis. The forward member rotates about a vertical steering axis. A saddle and footholds support the rider and allow the rider to balance and steer the device. The rider&#39;s hands never contact the vehicle but are used to propel the vehicle with the poles.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefits of U.S. Provisional Application No.61/792,921 filed Mar. 15, 2013, the disclosure of which is herebyincorporated by reference in its entirety including all figures, tables,and drawings.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT

Not applicable.

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC OR ASA TEXT FILED VIA THE OFFICE ELECTRONIC FILING SYSTEM (EFS-WEB)

Not applicable.

STATEMENT REGARDING PRIOR DISCLOSURE BY THE INVENTOR OR A JOINT INVENTOR

Not applicable.

BACKGROUND OF THE INVENTION

My invention is a velocipede—defined as a lightweight wheeled vehiclepropelled by the rider—in combination with a pair of hand-grasped polesby which it is propelled. The vehicle has just two wheels, which arealigned one following the other, referred to herein as two-wheel tandem.The bicycle and the scooter are examples of a two-wheel tandem vehiclethat appear very different, however both have the essential“two-wheeler” configuration that is commonly believed to include ahandlebar. In the invention the riders' hands are totally engaged withthe poles, and do not come in contact with the vehicle at all; andtherefor surprisingly, the vehicle is a two-wheeler without a handlebar.Poles on the other hand, have been suggested before as a means ofpropulsion in a lightweight wheeled vehicle.

Poles which have traditionally been used with skis are also used forbalance and propulsion of skis to which wheels have been added tonavigate hard surfaces (U.S. Pat. Nos. 2,545,543; and 3,389,922). Poleshave been provided to the users of roller skates for control, balance,and thrust (see, for example, WO 932588 and U.S. Pat. No. 5,601,299).Wheeled vehicles that allow the user to stand, sit, or kneel can bepropelled by poles. Poles used like oars can propel such a vehicle (U.S.Pat. Nos. 1,313,157; 1,425,220; 1,619,668; and 2,216,982). A single(U.S. Pat. Nos. 1,052,722; and 2,005,910) or multiple poles (U.S. Pat.Nos. 3,310,319; and 5,098,087) can also be used that are independentfrom the vehicle for propulsion as well as brakes on coasting vehicles.While some of these devices are designed to assist the movement ofparaplegics, most of the subject devices are intended for recreationaluse and to have fun.

Hwang, U.S. Pat. No. 5,125,687, described a rollerboard for road-skiing.The rollerboard has a rear wheel along a longitudinal line of the board,a front caster and subsidiary rollers to stabilize the platform. Theuser can either stand or sit on the platform. Poles are used to changedirection of the board. Chern, U.S. Pat. No. 4,863,182, attached a skateto a unicycle to create a sporting device that could be usedtraditionally as a unicycle by pedaling or as an ice or grass scooterwith poles to facilitate the sliding movement. A variety of vehicles ina variety of configurations to include two, three, four and more wheelshave been designed for use with poles, however, a two-wheel tandemvehicle does not appear among them.

In spite of the poles and lack of handlebars, the present inventionstill must conform to those same configurational requirements which alltwo-wheelers have in common, the ones that make it possible for a personto balance upon a moving frame supported by just two wheels on the road.Steering a two-wheel tandem vehicle is part of an active process bywhich the rider maintains their balance on the vehicle. And as such, thevital function of controlling the steering wheel by the use of therider's upper limbs, that is so integral to this process, must now beaccomplished by some other method, which the invention does by thefollowing scheme: The lower half of the rider's body is used to performthose functions which the upper half traditionally did by the use ofhandlebars, that is, stabilize the rider on the vehicle and steer itsforward wheel; so then the upper half of the body is free to be used topropel the vehicle, which is what the lower half normally did.

Although hands-free steering of a two-wheeler may have been thoughttheoretically possible, such means or method has not heretofore provedto be feasible. Barachet's (U.S. Pat. No. 5,160,155) proposed“Skateboard Having Two Wheels in Tandem” with its caster-mounted (wherethe wheel's point-of-contract with the road is aft of the steering axis)forward wheel may be such an attempt. Bryant, U.S. Pat. No. 6,488,295,also proposed a way that a two-wheeler might be modified to enable it tobe operated hands-free. Other experts, those skilled in the art, mayoffer their opinions—yet none can be found that would declare that it isnot possible—nevertheless, as far as can be determined by this inventor,it has not before now been successfully demonstrated.

In the year 1896, some twenty years or so into the development of themodern bicycle, Bicycles & Tricycles was published in England and becamethe foremost authoritative reference source on the design of thebicycle. Archibald Sharp, the author, analyzed every aspect of bicycledesign, including the phenomenon of riding one without holding thehandlebar. Economy of words, regarded as an attribute in writing duringthat period, can make Sharp's explanation on “Steering Without Hands”difficult to follow; however it does appear, the knowledge andunderstanding of the two-wheel tandem vehicle, as it pertains to thepresent invention, has not advanced since then.

Sharp presents four pages of analysis with diagrams and equations thattake into account the factors involved with steering a bicycle withoutthe use of the hands. Sharp assumes a rider can maintain equilibriumwithout touching the handlebar provided torque at the steering axisstays balanced; and therefore, forces acting on the front wheel andframe, which may tend to turn it about the steering axis, must becontrolled by the rider. Sharp recognizes two such forces which cancause various moments about the steering axis that tend to cause theposition of the front wheel to deviate from its mid-position (front andrear wheels heading in the same direction) whenever the vehicle istilted. One moment is due to the wheel's point-of-contract with the roadbeing out of alignment with that plane which includes the rear wheels'point-of-contact and the steering axis. The force that is associatedwith this “first moment” is a reaction to that weight which bears on thefront wheel.

A “second moment” is due to the center-of-mass—of that weight whichpivots about the steering axis itself—being offset from the steeringaxis. The force associated with said second moment is caused by thepull-of-gravity on this mass, which includes the weight of the frontwheel, fork, and anything else attached thereto, like a handlebar forinstance. The two moments tend to act in the same direction. A “thirdmoment”, which opposes or counter-balances the other two, is produced bycentripetal force at the front wheel's point-of-contract with the road,and is a reaction to the turning motion of the vehicle as it is beingridden. The centripetal force so generated is at right angle to thedirection of travel; and hence at any given moment in time, this forceis along the radius of the turn and in a direction pointing into thecenter of the turn.

Sharp derives an analytical expression for each of the three momentswhich take into account those factors mentioned above. According toSharp: “To maintain equilibrium the [summation of the analyticalexpressions for the three moments] should have the value zero, to steerfurther to one side or other it should have a small positive value, andto steer straighter a small negative value.” Sharp then points out: “Forgiven values of speed and steering angle, there remains an element, theinclination of the rear-frame, at the command of the rider; but evenwith a skilled rider the above moment varies probably so quickly that hecould not adjust the inclination quickly enough to preserveequilibrium.” It appears Sharp had little confidence that the factors inthis part of his analysis explained the feasibility of riding a bicyclewithout using the handlebar.

The 1890's were the golden age of bicycle design. Sharp and a handful ofother highly regarded bicycle experts of the time—most notable, Sharp'sprominent French contemporary M. Bourlet—spent a great deal of effortattempting to explain the secret of the two-wheel tandem vehicle.Agreement was never reached regarding the “no-hands” phenomenon. Andover the following century little if any improvement in the bicycle'sbasic design, or advancement in understanding, were made. In 1977 theMIT Press republished Sharp's Treatise, and in the foreword David GordonWilson, professor of mechanical engineering at the school, says this“definitive work . . . marked, and helped to bring about, the end of anexciting period in mechanical engineering . . . and was almost the lastbook as well as the last word on bicycle design.”

In today's modern era, those skilled in the art still hold theprevailing opinion from that earlier period. In U.S. Pat. No. 6,488,295Bryant states: “Particularly skilled riders can maintain stable, dynamicbalance of traditional bicycles traveling straight without holding thehandlebars. In such cases, they may even be able to turn their bicyclesleft or right simply by leaning their body and tilting the vehicle.However, minor transient disturbances, such as those associated withriding on an uneven or rough road surface, or the rider needing tochange speed or steering directions, quickly destabilize the vehicle”.Bryant asserts: “for any given two-wheeled vehicle, there is acontrollable operating envelope of speeds and turn radii for a giventerrain in which the rider's ability to simply tilt the vehicle in onedirection or the other is sufficient to correct dynamic instabilitiesarising during operation of the vehicle”, but because that “envelope ismuch smaller than desired . . . traditional two-wheeled vehicles arehand-steered”. Bryant believes that he knows a way to correct thiscondition and thereby eliminate the need for handlebars.

Bryant's apparent revelation: “A previously unrecognized, but majorfactor in two-wheeled vehicle stability is the un-stabilizing forceassociated with the point-of-contact of the steering wheel, which ispivotally secured to the vehicle along the steering axis, being spacedtoo far away from the vehicle plane, defined as the plane that includesthe rear wheel's point-of-contact and the steering axis, when thesteering wheel is turned” is of course the very same force recognized bySharp and presented in his 1896 Treatise, as cited herein, and thatbeing the cause of said “first moment” referred to above. And like Sharpbefore him, Bryant realizes that this “major factor” can generate torqueabout the steering axis. Bryant does not, however, recognize Sharp's“second moment” which can also cause torque about the steering axis.

Bryant does not attempt to improve the hands-free handling capability ofthe bicycle in general. Bryant's objective is to take a giventwo-wheeled vehicle and make it stable and controllable within an“operational envelope”—and eliminate the necessity for a handlebar—byincorporating a “dynamic control regulator” which, by mechanical means,can vary the geometry of the vehicle as a function of its tilt andsteering angle. Bryant's proposes several designs for such a vehiclewhere “the rider stands on a substantially planar standing surface inthe same manner as a rider of a surfboard, snowboard, or skateboard” andsteers by leaning their body in the same hands-free manner.

Interestingly, in his discussion of the state-of-the-art, Bryant refersto the 1995 second edition of Bicycling Science—where the same DavidWilson that helped get Sharp's 1896 book republished, and who concludesin his book: “the balancing and steering of bicycles is an extremelycomplex subject on which there is a great deal of experience and ratherlittle science”—as “another example of the limitations found withconventional analysis of two-wheeled vehicles.” Archibald Sharp, CarloBourlet, David Wilson and Robert Bryant can all be considered experts onsteering and stability of a two wheel tandem vehicles, however they donot form a consensus on the subject. Although many experts in theengineering and design of the bicycle have studied and analyzed thetopic of steering and balance, the fact remains, over this long period,as far as known, nobody has succeeded in making a rideable two-wheeltandem vehicle that operates without a handlebar.

In his third edition of Bicycling Science, in which Wilson comments onwhy he decided to have Jim Papadopoulos write the chapter on steeringand balancing—“the chapter on the topic that I wrote for the secondedition . . . was the least satisfactory in the book”—Wilson remarksthat over the years he has “found, through sending the drafts out toexperts for review, that there seemed to be no agreement among expertson the topic.” Papadopoulos, who is “a graduate of MIT with a Ph.D. inmechanical engineering, some-one who has devoted his life to theimprovement of scientific and engineering knowledge of bicycles andbicycling”, writes in the introduction of the chapter: “Unfortunately,the mathematics purporting to describe bicycle motion and self-stabilityare difficult and have not been validated experimentally, so designguidance remains highly empirical.” At the end of the chapter,Papadopoulos cites thirty seven references, including Sharp and threeother experts from a hundred plus years earlier, in support of thisfinding.

All patents, patent applications, provisional patent applications andpublications referred to or cited herein, are incorporated by referencein their entirety to the extent they are not inconsistent with theteachings of the specification.

BRIEF SUMMARY OF THE INVENTION

The invention is a velocipede—defined as a lightweight wheeled vehiclepropelled by the rider—in combination with a pair of hand-grasped polesby which it is propelled. A forward member and a rearward member of thevehicle define a longitudinal axis. A forward wheel and a rear wheel aremounted to the forward members and rearward members, respectively, andalign along the longitudinal axis. The forward member rotates about asubstantially vertical steering axis which intersects the longitudinalaxis defining a plane. The rear member is positioned on the plane andjoined with the forward member along the steering axis. A saddle isconnected to the rearward member of the vehicle. Footholds can bepositioned on the forward or rearward member. The footholds and a saddlesupport a rider in a substantially upright position, facing forward withhands gripping the poles, while balancing astride the moving memberswhich are supported on the axles of the two wheels.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a side elevational view of a preferred embodiment of thevehicle of the subject invention.

FIG. 2 is a front elevational view of the preferred embodiment of thevehicle shown in FIG. 1.

FIG. 3 is a side elevational view of the preferred embodiment of thevehicle of the subject invention shown in FIGS. 1 and 2 with a ridermounted on the vehicle shown in phantom.

FIG. 4 is a side elevational view of another preferred embodiment of thevehicle of the subject invention.

FIG. 5 is an environmental view of the preferred embodiment of thevehicle shown in FIG. 4 showing a rider with poles seated on thevehicle.

FIG. 6 is a side elevational view of another preferred embodiment of thevehicle of the subject invention.

FIG. 7 is a partial side view of a preferred embodiment of a brakeactuator on the vehicle of the subject invention.

DETAILED DESCRIPTION OF THE INVENTION Concept

Although a pole-driven cycle cannot be regarded as a suitable means fortransportation, this deceptively simple concept can produce analtogether unique recreational ride that is both fun and healthy. Like abicycle it provides great outdoor exercise, but instead of muscular legsit builds upper body strength, especially strong arms and shoulders. Itallows a rider to use and experience their sense of balance, and improvetheir coordination. The rider can stop anytime without dismounting; andunlike in other apparatuses which are used for recreationalactivity—including skis, skates, skateboards, bicycles and scooters—therider can remain comfortably seated, and rest while talking at length ontheir cell phone if so inclined. It is lightweight too, and can beeasily carried—up or down stairs for instance.

An especially important feature of the invention is that the vehicle canbe operated in either one of two modes: it can be ridden or it can bewalked. And just as it is as likely to see a skateboard being carried asridden, it is foreseen too that this vehicle will likely be seen“walked” as ridden. It is meant to share the sidewalks with pedestrians,like a scooter; and hence, operating at walking-pace speeds and slower,in either the walking mode or riding mode, was an important goal of theinvention. It works well too at jogging and running speeds, in eithermode, making it ideal for riding on neighborhood streets and bike paths.The new riding method created by the odd combination of this faintlyfamiliar looking apparatus being propelled about by a pair ofhand-grasped poles has a natural maneuverability which heretofore wasunanticipated.

During those times in the course of a ride, due to unfavorable ridingconditions, or any reason, the rider may wish to continue on foot byusing the vehicle in its walking mode. The rider then can progress bywalking to the side of the vehicle as it is pushed forward by one hand.It is a most natural process. Now afoot, the rider can carry the polesin one hand—or place them in a special holder attached to thevehicle—while gripping the saddle with the other and either walk or runalongside the gliding cycle. The rider steers by a simple twistingmotion to the saddle. The cycle responds instantly and precisely to suchcommands without interfering in any way with the walking or jogging ofthe user. The self-steering cycle can be confidently “walked” in thismanner without the need to look down at it or the road. Its largediameter front wheel and light weight allow it to be “walked” just aseasily on paths or other unimproved surfaces.

The rider's distinctive stance differentiates the invention from othertwo-wheelers: The rider is seated in a sitting position with an uprighttorso, clutching poles; the thighs are bent forward at the hips, withthe lower legs bent downward at the knee in a near vertical position,with the feet placed on footholds attached to either side of thevehicle. The rider's arms and hands are totally engaged with the poles:the upper body does not come in contract with the vehicle at all. Fromthe waist up the rider resembles a cross-country skier, and indeed,moving forward using similar arm motions and upper body actions, itwould at first glance appear so. Waist down however, the rider wouldseem more on horseback, supported by a saddle and footholds, astride thecycle with lower limbs pressing the frame. The primary purpose of thepoles may be propulsion, but nevertheless, just like a skier would notattempt skiing without their poles, the rider would not contemplate itsuse without the security of the poles.

Two Wheel Tandem Vehicle

Employment of poles as a means of propulsion is ideally suited to atwo-wheel tandem vehicle. It is surprising so many factors contribute totheir successful use for this purpose. The rider's forward-facingupright stance and stable position in relation to the direction oftravel are both essential factors. The narrow tract of the vehicle lendsitself to poling—that is, propelling the cycle forward by the thrustingaction of hand-grasped poles. The rider can lean their torso to extendtheir reach, either forward or backward, while applying varying amountsof force to the poles, either stroking with one at a time or both atonce without interfering with the cycle's operation. And the rider'sbody itself, with its shoulders broader than its hips, and arms thatbend and rotate in the direction of travel are perfect for the task. Thefact that the vehicle has excellent coasting capability is a necessarycondition.

On the other hand, a two-wheel tandem vehicle is inherently unstable andunable to stay upright on its own. Its operation is also the leastunderstood of all wheeled vehicles, which has made it a challengingchoice for a vehicle that could be successfully adapted to poling. Theinvention's unique ride is in part derived from the handlingcharacteristics of the vehicle's two-wheel tandem configuration; and itwas primary for this reason that this basic form was selected. Thus as agiven, there are two critical factors that are peculiar to this type ofvehicle—balance and stability—that must be dealt with. Balance can bethought of as that factor associated with the rider's ability to keepthe moving vehicle upright; and stability is herein associated with therider's ability to stabilize their body on the moving vehicle itself.The two factors are interrelated; one cannot happen without the other;and every aspect of the vehicle's setup and operation, with respect tothe rider, is affected by them. And thus, in the present invention is aresult of the successful resolution of these two critical factors.

It has been determined by the inventor that said balance and saidstability can be achieved while operating a two-wheel tandem vehiclewithout a handlebar; and it can be achieved concurrently with, andindependently of, the rider's use of hand-held poles; and under certainconditions, or in certain situations, or during certain maneuvers, whereit would not otherwise be, it can be achieved with the assistance of, orin conjunction with, the rider's use of hand-held poles. Reference tothe rider's use of poles means: the rider's upper body makesintermittent contact with the ground or roadway via a pair of hand-heldpoles; and, although the primary function of the poles is to propel thevehicle forward by applying those thrusting actions which run parallelwith the vehicle's direction of travel, other actions involving the useof the poles can be performed by the rider for reasons other thanpropulsion, such as those actions which a rider may perform that arerelated to said balance and that can assist in steering the vehicle, asherein disclosed.

Reference to a two-wheel tandem vehicle or configuration, ortwo-wheeler, herein means: a velocipede having two inline wheels, thatis one wheel following the other, and two structural members which carrythe weight, or mass, of the rider: the forward member 10 to which theforward wheel 12 is attached and the rearward member 14 to which therearward wheel 16 is attached. The forward member is pivotally connectedto the rearward member at the steering tube 17. Described moretechnically: the forward member and rearward member define alongitudinal axis, forward wheel and rear wheel mounted respectivelythereto and aligned along the longitudinal axis L; the forward memberrotatory about a substantially vertical steering axis S; the steeringaxis intersecting the longitudinal axis defining a plane P; the rearwardmember 14 positioned on the plane and joined with the forward member 12along the steering axis. It is important to note that the setup of atwo-wheel tandem vehicle, that is the rider's position with respect tothe vehicle, is fundamental: The weight of the rider is carried by, andheld largely between, the axles 18 a, 18 b of the two wheels; and theweight of the rider is evenly distributed, that is balanced laterally,on each side of the vehicle's longitudinal axis, which would be the casewith a rider straddling such a vehicle.

Using Poles

The operation of wheeled vehicles is controlled through their connectionwith the riding surface via their wheels. In three or four-wheeledvehicles the interface between the user and road is straightforward andtaken for granted. However in a two-wheel tandem vehicle this interfaceis complex due to the active participation required by the operator inkeeping the vehicle balanced upright. In the invention the relationshipbetween the operator and the vehicle is further complicated by the useof poles 24, which introduce an additional connection with the ridingsurface. As a result, two separate and independent control channelsexist between the operator and the roadway: The one through the rider'slower body via the two wheels, which is in part controlled by therider's feet and legs; and the other through the rider's upper body viahand-grasped poles, which is controlled in part by the rider's arms.

It may be difficult to envision the coordination of seemingly unrelatedmovements which the rider must perform to ride the cycle. To thoseskilled in bicycle design, it may seem that the use of a pair ofhand-grasped poles as a means of propulsion in a two-wheel tandemvehicle would be impractical, and likely to overly complicate andcompromise its operation. This inventor has demonstrated that this isnot the case with the two-wheel tandem vehicle that is described hereinas the preferred embodiment. The use of poles does not interfere withsaid balance or said stability; and in fact, the use of poles canbenefit and extend the function and performance of said vehicle. And ofutmost relevance, it was discovered that the use of poles in a two-wheeltandem vehicle, as a means for propulsion, or for the purpose ofextending the function or performance of the vehicle, is intuitive.

The use of the poles can be especially advantageous at velocities whichare at the lower end of the vehicles speed range, where they can play apart in steering the vehicle and in aiding the rider in certainmaneuvers. For instance, in preparation for turning to the oppositedirection, the rider can use the poles to help push the vehicle upright,thereby raising its center-of-mass so that the rider can then tilt thevehicle to the opposite side of its longitudinal axis. Or in anothermaneuver, the poles can be used to prevent the vehicle from fallinginward during the execution of a tight turn, where the vehicle may tendto sharpen the radius, a phenomenon known in other two-wheel tandemvehicles. In such a case, the rider would lean on that pole that istoward the inside of the turn, and thereby preventing the vehicle fromfalling. It may be noted that in these examples the poles are used togenerate force that is perpendicular to the direction of travel, andtherefore illustrate that poles can indeed be used for a function otherthan propulsion.

Furthermore, it has also been demonstrated by the inventor, whencoasting on a model of the preferred embodiment, as the speed of thecycle deceases, there exists a velocity below which the rider cannotmaintain their balance without resorting to the aid of the poles. Belowthis velocity, which can extend downward to where the vehicle has cometo a near standstill, a rider can use the poles in a way that canprevent the cycle from falling to one side or the other as it travelsmore or less straight ahead. It should be noted, therefore, that withthe aid of the poles the cycle is capable of operating in a mode that isnot consistent with that of a two-wheel tandem vehicle. From what hasbeen discovered, it seems reasonable to presume that with a littlepractice the rider can learn to manipulate the poles in a manner thatcan add a dimension of maneuverability that is not possible at slowspeeds in other two-wheelers. Also the poles were found to beparticularly useful when initiating and terminating a ride, substitutingas the “feet” on the pavement during those times, so the rider's realfeet can stay on the footholds.

Stability and Balance

To help one understand the dynamics involved in operating the vehicle,the forces that bear on the vehicle which affect said balance and saidstability can be differentiated with respect to the vehicle'slongitudinal axis, which is closely associated with the direction oftravel. A force, or component of a force, that is aligned with thevehicle's longitudinal axis cannot tip the vehicle. The end result isthat said stability—that is a rider's ability to stay on the vehicle bybeing able to firmly attach their body to the vehicle at will—and saidbalance—that is the rider's ability to keep the vehicle upright—are onlyaffected by force in a lateral direction, one which is normal to thevehicle's longitudinal axis. Consequently, a force that bears on thevehicle and rider, for example gravity, wind, or stress caused byvarying road conditions, regardless of the direction of that force, canonly tip the vehicle sideways.

If the question of said stability can be resolved, said balance becomesprimarily an intrinsic function of the vehicle, based on its two-wheeltandem configuration and its setup, whereby the rider is enabled tospontaneously “catch their balance” by slightly pivoting the vehiclesforward wheel to one side or the other in the direction in which theyfeel they are falling. Think of a broomstick being balanced verticallyon the palm of one's hand, which must be continually moved in thedirection in which it starts to fall in order to maintain its balance.In the case of a two-wheel tandem vehicle, it needs to be moving forwardfor this to work; and there is also a minimum forward velocity that isassociated with its particular design, as in all two-wheelers, belowwhich it becomes difficult for the rider to keep their equilibrium. Saidbalance cannot be discussed further without including the subject ofsteering, both of which are addressed together in detail herein.

On the other hand, said stability, becomes problematic without ahandlebar. All preceding two-wheel tandem vehicles have relied on thehandlebar to stabilize the rider on the vehicle. In the invention, someother means must fulfill this function, and its design will need toassure that a rider can safely stay mounted when operating the vehiclein general, as described herein, and do so while poling in allsituations, including starting and stopping, and maneuvering undervaried road conditions. The rider's lower limbs are required to providethis crucial support, that is the stabilization of the rider's body onthe vehicle, while at the same time performing those subtlemanipulations of the vehicle's forward wheel that are needed to steerand maintain its balance. These seemingly incompatible functions showwhy the concept calls stability into question.

It has been determined by the inventor that the support of the rider'sbody weight on the vehicle can be achieved by the employment of therider's lower body; and this can be accomplished by using support meanspositioned at three points on the rider's body—at the buttock and bothlegs and or feet. According to the invention, a saddle 20 and footholds22 are those support means which can be used for this purpose. Inaccordance with the invention, as normally ridden, a rider maintainsconstant contact between the three points and the support means. Undercertain conditions, or when making certain maneuvers, especially duringthose times that one or both poles 24 are making contact with theroadway, varying amounts of the rider's weight may be shifted betweenthe three support means, or between one or more of the three supportmeans to one or the other or to both poles.

According to the invention, the buttocks and feet are the primarypoints-of-contact on a rider's body that engage the vehicle; and duringthe time that the vehicle is being ridden, they maintain contact withthe vehicle. However, other parts of a rider's body can be employed toaid and assist the rider in stabilizing their body on the vehicle. Suchadditional contact between the rider's body and the vehicle would beaccessory, or supplementary, to said primary points-of-contact. Whereasa primary point-of-contact passively engages the support means in orderto support a rider's mass on the vehicle and thereby counter theforce-of-gravity, employment of an accessory point-of-contact on arider's body requires active engagement, that is the contraction of therider's muscles, in order to engage an accessory contact means, and canthereby counter lateral force. When accessory contact means are soengaged, the rider's lower body forms a rigid connection with thevehicle, which often is necessary to provide said stability. In thisregard, use of an accessory contact means can be temporary andintermittent even though that part of the rider's body which engagessuch means remains in contact with the accessory contact means after thecompletion of the task for which it was temporary employed.

The purpose of an accessory contact means is to provide a rider with anadditional connection to the vehicle that can help the rider counter astate of temporary unsteadiness on the vehicle, where the use of thefootholds and saddle alone may not suffice. A momentary condition oflateral instability, for instance, which might result from torque causedby foot-steering or poling, or maybe a sudden turn, could be such asituation. The riders' knees or thighs, for example, can be employed asthe accessory contact points to handle these types of situations. Theaccessory contact means 26 can be positioned on either side of thesteering tube 17, for instance, with surfaces that conform to the innerthighs and or knees, which the rider can press or clamp their thighs orknees against when needed. The front of the saddle can also be extendedforward between the rider's thighs for this same purpose. Either way arider can, in a moment's time, engage five points-of-contact on thevehicle—two footholds 22, the saddle 20, and two knee or thigh presspoints of the accessory contact means 26—and thereby stabilize theirbody on the vehicle.

It should be noted, as an alternative to said accessory contact means atthe steering tube, or in addition to, stability could be enhanced byadding accessory contact between the rider's upper body and the vehicle.For instance, the forward part of the saddle can be extended upwardbetween the rider's legs to form a brace with means attached theretowhich enable the rider to engage their abdomen or chest, and therebyform a rigid connection between rider and vehicle. Such means would notinterfere with a rider's ability to use the poles, nor the mounting ofthe vehicle, which can be done from the rear. Although the purpose ofsuch an accessory contact would be primarily to improve the riders'lateral stability, it can protect the rider from injury during an abruptstop or crash. It should also be noted that an actuator for a brake 28to stop or slow the vehicle can be incorporated into, or made a part of,the means by which an accessory contact is implemented.

It is important to realize that with respect to said stability, therider's use of the footholds is not equivalent to that of a handlebar.The footholds suffer from an obvious disadvantage. Unlike a handlebars,which are controlled by the very nimble arm-hand combination, footholdsinterface with the more sluggish leg-foot duo. The anatomicaldeficiencies of the latter for the purpose of stabilizing the rider'sbody on the vehicle, also present other challenges. The hand-gripingfunction, which enables the arm-hand combination to engage in both apushing and a pulling action, and which is an essential capability forbracing the rider in all other two-wheeler type vehicles, cannot beemulated in the present invention through the employment of the rider'slower limbs. Although the rider's use of the saddle, footholds andaccessory contact means together may not fully compensate for the lackof a handlebar, the stability that is achieved is sufficient to ride thevehicle within the intended speed range of the invention.

Nevertheless, the shortcomings of the lower limbs as a substitute forthe upper limbs need not result in the handicap of the vehicle, althoughthe limitations imposed may be significant. The purpose of thisinvention is recreation, and therefore handling, and othercharacteristics of the vehicle, do not necessarily equate to theperformance requirements of other vehicles, which may have otherpurposes. Things like slow-speed operation, and the unusualmaneuverability, are meant to add interest to the invention and make itfun to use. It should be noted however, that the rider's use of polescan make up for this deficiency to some extent; and in the case of slowvehicle speed, the poles can assist the rider in ways in whichhandlebars cannot, and thereby extend the cycle's low velocity handlingcharacteristics.

Steering and Mass

It is important to realize that in a two-wheeler said balance and thesteering of the vehicle are really one in the same process. The cycle isnot steered in the same sense as in other vehicles with three or fourwheels, where an operator can accurately control the vehicle's directionby the use of a mechanical means for such purpose. The cycle is moreindirectly steered, or urged, by the rider to progress in the desireddirection, the actual course not being in a straight line, but based on,and secondary to, said balance. The process by which this takes placeinvolves the lateral shifting of the rider's weight in conjunction withthe direct manipulation of the angle of the vehicle's forward wheel,which prior to the present invention was accomplished through the use ofa handlebar. In said process, rider and cycle become one, and worktogether as parts in a complicated maneuver that steers the vehicle—thatis keeps it from falling, and headed in the desired direction. Therider's influence is subtle and intuitive, and difficult to quantify;but it is evident that the rider's mass and body English play animportant role.

The rider's relative mass to that of the cycle is many times greater;and therefore, depending on the position of the rider with respect tothe wheels, there can be a significant difference in that mass which issupported by each wheel. This can be an important factor in the handlingof a two-wheeler. Nevertheless, during the long history of the bicycle,the saddle, which supports the major share of a rider's mass, has beenpositioned more or less over its entire length: from close proximity tothe front axle in the “high wheeler” designs in its early history, tonear the rear axle in some recumbent designs. For the most part, itsposition has been based on the location of the pedal crank, even thoughthat position may have resulted in the less-than-ideal placement of therider's mass on the vehicle. Furthermore, a rider's mass can move abouton the vehicle: The pedal crank can be used in ways that can cause therider's mass to shift from side-to-side, for instance when standing onone pedal. Also, the weight that the rider places, or the force exerted,on the handlebar can vary too, which can cause mass to shift fromwheel-to-wheel.

On a bicycle, with the aid of handlebars the rider is able to overcomethe disadvantage that may be caused by the less-than-ideal placement oftheir mass, or the shifting about of their mass, with respect to thevehicle. The process of balancing and steering is dominated by the useof the handlebars; whereas the mass of the rider plays a minor role. Inthe invention however, the less-than-ideal placement of the rider's masson the cycle, or the shifting about of that mass during operation of thevehicle, can complicate and interfere with said balance and steering, asexplained herein. According to the invention, a rider's mass issupported on the cycle in a more or less fixed position by the saddleand footholds; and it can be further steadied laterally, and braced inthat fixed position, with the aid of the accessory contact means; and asa result, that portion of the rider's weight which is carried by eachwheel remains more or less constant during the operation of the cycle.

According to the invention, the location of the footholds and saddle onthe cycle determines the distribution of the rider's mass between thewheels; and the placement of the footholds and saddle on the vehicle canbe critical to the operation and performance of the cycle, as explainedherein. It should be noted that the position of the rider's legs andfeet do not suffer restriction in their placement like that imposed inthe design of the bicycle where the pedal crank, for example, determinesthe location of the rider's legs and feet. Therefore, any similarity orparallelism in the location of the saddle and footholds with that of anyother two-wheel tandem vehicle, such as in earlier designs of thebicycle known as a “high wheeler,” or in its modern configuration, iscoincidental. As in the case of the bicycle, however, the saddle'slocation on the cycle is subordinate to the requirements of the functionof the rider's legs and feet with respect to the operation of thevehicle.

In the control of the cycle in the invention, the significance of therider's mass is that it relates to the development of torque about thecycle's steering axis. Said torque is a major factor in the process bywhich said balance and steering take place. It is important tounderstand that in said process, the control and determination of thedirection of the steering wheel is dependent on several factors whichcan cause the steering wheel to pivot about the steering axis, the mostobvious being the movement of the footholds by the rider's feet. Torqueabout the steering axis can also cause the steering wheel to pivot. Whena rider leans their torso sideways, the cycle also tilts; and theinclination of the cycle's forward member can cause said torque.Retaining the rider's mass in a fixed position, and assuring that it canbe held rigidly to the rearward member, prevents the torque from varyingas a result of shifting weight on the forward wheel.

According to the invention, that mass which bears on the steeringwheel's point-of-contact with the ground can be a major factor in thegeneration of torque about the steering axis, and as such, this mass canbe a critical factor in the steering and balance of the cycle.Furthermore, said torque can be differentiated into two components, bothof which rely on and exploit said mass, or a portion thereof. A firstcomponent of said torque is a function of the total weight of said mass.A second component of said torque is a function of only that portion ofthe weight of said mass which pivots with the steering wheel; and thismass has associated with it a center-of-mass which is located forward ofthe steering axis. It should be noted that the mass which bears on therear wheel of the cycle has no effect on said torque.

It has been determined by the inventor that said balance and steering ina two-wheel tandem vehicle, as described herein as the preferredembodiment, can be achieved, in part, by using a technique by which thetorque about the steering axis is manipulated and controlled by therider. Using this technique, the direction of the steering wheel—that isthe steering angle—can be continually varied by the coordinated actionsof the rider's torso and feet; and in so doing, the equilibrium andcourse of the vehicle can be maintain. In particular, said torqueresponds to the degree to which the rider leans their torso with respectto the cycle's longitudinal axis; and that response can be modified,either damped or augmented, though the manipulation of the forwardmember by the use of the rider's feet.

Vehicle Layout

According to the invention, the rider's place on the vehicle is definedby the location of the saddle and the footholds. The saddle is fixed inposition to the rearward member, which is the case in most two-wheeltandem vehicles. With the footholds there is a choice between locatingthem on the forward member or the rearward member. Early bicycles withtheir front-wheel drive, and modern ones with their rear-wheel drive,demonstrate that footholds can be mounted to either member withoutcompromising the vehicle's two-wheel tandem configuration. It may bethat the principles according to the invention could be applied to avehicle with either arrangement, although their designs, and probablytheir operating characteristics, would differ. In either arrangement therider would maintain the same stance and use of the poles. And thoseremarks pertaining to accessory contact means would be applicable,except for attaching such means to the steering tube, which would applyonly to the former case.

Placing the footholds on the forward member has significant advantagesover that of the rearward member and is thus preferred. As a practicalmatter, in the latter case, the rider's use of their feet to control thepivoting of the steering wheel would be accomplished indirectly via amechanism located between the vehicle's wheels, which would require alinkage 30 that connects it to the steering fork 21. Such a mechanismmay be awkward to use and its linkage to the forward member could bevulnerable. Both the mechanism and linkage would be eliminated byplacing the footholds on the forward member. Furthermore in doing so,two very important benefits will result: The rider's mass can be shiftedtoward; and, the vehicle's wheelbase can be shortened since space forthe rider's legs and feet would not have to be allocated between the twowheels. These benefits improve said balance and steering.

Nevertheless, a pole driven two-wheel tandem vehicle with the footholdlocated between its wheels may be feasible. FIG. 6 illustrates theconcept of such a vehicle. In this example, the rider's feet can controlthe pivoting of the steering wheel by their up-down movement of theforward part 32 of the foothold with respect to the rearward support peg36, on which the heel of the foot rests. Note that to make the steeringwheel deviate from its straight-ahead orientation, a reciprocatingmotion of the forward part of the two footholds is required—to turn thesteering wheel to the right, the right foot rotates downward while theleft foot rotates up. Alternatively, a mechanism and linkage operated bya forward-rearward motion of the rider's foot could be employed. Ineither case, it has not been determined whether such motion can beperformed intuitively by a rider of such a vehicle. Although, a vehiclewith its footholds attached to its rearward member falls within thescope of the invention, for the sake of clarity, all remarks hereinshall apply specifically to that version of the vehicle in which thefootholds are attached to the forward member, even though those remarksmay also be applicable to the other. Reference to the cycle in theinvention, or the model of the cycle, or the preferred embodiment shallrefer to that case where the footholds are attached to the forwardmember.

By placing the footholds on the forward member, the rider's mass can bepositioned further forward on the cycle than would otherwise bepossible. The further forward the rider's mass, the more easily andfaster it is to move that weight about laterally, and hence the easierit is for the rider to maintain their equilibrium. It should be notedthat the quicker the cycle responses to changes in the steering anglethe slower the speed at which the cycle can be operated. The shorteningof the wheelbase is significant because it also contributes to thecycle's slow-speed riding capability, as explained herein. It should benoted that the wheelbase can be shortened further by reducing thediameter of the rear wheel thereby placing the wheel axles 18 a, 18 beven closer together. It should also be noted, that the shorter thewheelbase, the quicker the cycle responds to the twisting commands ofthe user's hand during the walking mode.

In the preferred embodiment, the position of a rider's legs with respectto the steering wheel is an important consideration. Due to the forwardposition of the saddle on the rear member, and as a result of thesaddle's height above the steering wheel, the rider thighs can beextended forward over the top of the steering wheel, making them more orless horizontal, and thereby placing the knees forward of the steeringtube. This permits the rider's legs to be situated so that they do notinterfere with the steering wheel as it pivots to the left or right. Theknees can be set apart by the accessory contact means, which can belocated on either side of the steering tube, and would therefore makecontact advantageously with the rider's inner tights. The span betweenthe knees would be preferably equal to, and determined by, that by whichthe footholds are set apart. The knees would then bend downward, therebypermitting the lower legs—the shanks—to run parallel more or less withthe steering axis, so that the feet end up at the correct points oneither side of the steering wheel.

It is this orientation of the thighs, knees, shanks and feet that allowsthe rider's legs to remain more or less fixed in place as the steeringwheel is being pivoted. The shanks are capable of pivoting withoutmoving the knees, so that then the feet rotate on the footholds in thedirection of the pivoting wheel, and thereby avoid striking the spokes,the shanks remain parallel to the steering axis. As the turning radiusof the cycle decreases, it may be noticed that the foot to the inside ofthe turn moves rearward while the one on the outside moves forward. Therider can easily perform the necessary maneuver in a natural manner byswiveling the feet together in unison with the pivoting wheel. Even atvery slow speeds, and where the sweep that the footholds make about thesteering axis reaches its maximum limit, and where the rider may need touse the poles to keep their balance, the rider is still able to controlthe pivoting of the steering wheel with their feet.

It is important to note that the rider's lower body remains more or lessstationary during the operation of the cycle even though the feet swivelwith the pivoting of the fork. The rider can perform the necessarymaneuvering of the footholds without disturbing the body's position onthe cycle. This is significant because it permits the insides of thethighs or knees to engage an accessory contact means, at any time, byusing the strength of the muscles of the inner thighs to clench saidmeans between them, and thereby form a rigid connection between therider and the rearward member. During the same time, or at any other,the rider can apply inward force on the footholds by pressing the feetinward toward each other, thereby providing addition rigidity to thelower legs. In this situation, it may be said that the foothold is alsoacting as an accessory contact means. The rider can also apply lateralforce to one accessory contact means or the other, or one foothold orthe other, or a combination thereof. These actions are performedintuitively by the rider without a noticeable effect on the overallhandling of the vehicle.

Preferred Embodiment

A preferred embodiment of the vehicle of the subject invention is shownin FIG. 1-3. This rideable two-wheel tandem vehicle is ridden where thebody of the rider, from the waist up, makes no contact with the vehicle.It is easily ridden, and surprisingly smooth-riding and agile; and withthe aid of the poles, this inventor was able to easily executedfigure-eight's for example, at a very slow speed—much slower than atraditional bicycle can do—in an area less than the size of a single-carparking spot. In FIG. 4 said preferred embodiment is shown with thesaddle integrated with the accessory contact means. The vehicle in FIG.4 is shown in operation in FIG. 5. In FIG. 1-3 the foothold is shown inits most basic form where a single peg 36 under the arch of the rider'sfoot supports the weight of the leg. In FIG. 4-5 an example of afoothold is shown with a lower support and upper component, both ofwhich can be positioned differently than shown. The upper component canresist upward force applied by the foot. It should be noted that theactuator for the rear wheel brake 28, which is preferably incorporatedinto the foothold, is not shown in FIG. 1-5.

In FIG. 6 a representation is shown of another embodiment of the cyclesaccording to the invention. In this embodiment, the footholds would beon the rearward member of the vehicle. It should be noted that in thesubject representation has no brake as shown; the combined saddle andaccessory contact means appear not to be braced; the forward member isnot shown with offset mass, which would be required for the generationof torque by said second moment or method, as described herein; and, hasother overlooked details that are apparent.

In the preferred embodiment, the footholds 22 are located on the forwardmember 10, one on each side of the front wheel or steering wheel 12; theaccessory contact means 26 are located on either side of the steeringtube 17 with respect to the longitudinal axis; and, the saddle 20 islocated on the rearward member 14 fixed at a height above the groundthat permits the rider to place their feet on the ground while sittingon the saddle with their legs straddling the cycle. The position of thesaddle with respect to the steering axis is based on, and establishedby, the position of the footholds. The footholds are attached to thelegs 19 of the steering fork 21 in such a position that that part of thefoothold which supports the weight of the rider's foot and leg islocated forward of the steering axis. A conventional bicycle brake 28that is operative on the rear wheel 16 is controlled by a part of therider's body, preferably the foot. A pair of hand-grasped poles 24having hand grips on one end and rubber pads, or tips, on the other areprovided for use by the rider.

The position of the footholds with respect to the center of the steeringwheel (that is the axle 18 a), and the position of the saddle withrespect to the steering tube 17 and the riding surface, are dependent inpart on the rider's leg size; and therefore, the position of thefootholds and the saddle are both adjustable. For a given rider, theoptimum position of the footholds and the saddle can be determined asfollows: First, the height of the saddle is set above the ground suchthat the rider's feet rest on the ground when the rider is seated at astandstill. Then, the initial fore-aft adjustment of the saddle is setso that when the rider's thighs are bent forward placing them above thesteering wheel, the inner thighs, back from the knees, are able to pressagainst the accessory contact means on either side of the steering tube.The knee's then extend beyond the steering tube (and preferably theaccessory contact means) and bend downward so that the shanks of thelegs run more or less parallel to the steering fork. The footholds canthen be set such that their initial position places the shanks of thelegs forward of the steering axis on either side of the fork. At thispoint, the vehicle should handle reasonably well. For each rider thereexists a sweet spot, or optimum position, for their feet, and thecorresponding position of the footholds can be found by test riding thecycle. The vehicle can be further tuned to the rider by adjusting firstthe fore-aft position of the footholds, then readjusting the fore-aftposition of the saddle if necessary; and then after each such adjustmentof the footholds, the vehicle should be road-tested again.

In the model of the preferred embodiment of the cycle shown in FIG. 1,the form of the rearward member 14, that is the cycle's frame, and thatof the forward member 10, that is its steering fork, may appear similarto that of other known two-wheel tandem vehicles. The single-tube“backbone” type frame connects at one end to a 9 inch rear fork 13 towhich a 16 inch diameter standard bicycle wheel mounts. The selection ofthe rear wheel 16 diameter was based in part on minimizing the cycle'sweight and wheelbase. The other end of the frame connects to a 7 inchlong steering tube 17 which mates with a 17 inch straight steering fork21, which has no offset—that is the steering axis intersects the axle ofthe wheel. A 28 inch diameter standard bicycle wheel mounts to the fork.The diameter of the steering wheel 12 was specified as large aspossible, it being restricted by the rider's ability to lower their feetto the road when seated in the saddle. The trail (defined herein) wasset at about 4 inches; and the wheelbase at approximately 25 inches.Pole lengths of both 48 inches and 53 inches were used. A common bicyclesaddle 20 attaches to a post which is connected to the frameapproximately 8 inches back from the steering tube.

The size and shape of the accessory contact means 26 can vary. In themodel, as shown in FIG. 1-3, the outward facing surfaces of said means,which contact the rider's inside thighs, are about 4 inches wide by 6inches in height with a slightly concave shape that conform to therider's thigh. The forward edges of said two surfaces are about 6 inchesapart at their narrowest point, thus separating to the rider's knee bythis amount, and taper in to about 4-5 inches apart at their rearwardedges. The size and shape of said surfaces is not critical—ones thatwere half as wide seemed to work just as well. The accessory contactmeans can be separated into two parts, there being a left-thigh contactand a right-thigh one. The accessory contact means can also engage theinward sides of the rider's knees, either together with the thigh orinstead of; however, it is important that that they do not interferewith the movement of the shanks with respect to the knees. It isimportant that said surfaces be firm and rigidly attached to therearward member.

The shape of the footholds 22 can also vary, there being no restrictionon their form except that of supporting the weight of the rider's legsand feet, and that of being capable of bracing against inward lateral(toward the wheel) force which the rider may apply with their feet. Theposition of the foothold is adjustable up-down and forward-aft, asillustrated in FIG. 1 by the four holes in its mounting bracket—whichallow the perpendicular support peg 36 that points outward to beadjusted horizontally—and by its rotatable position with respect to thewheel's axle—which allow the peg to be adjusted vertically. Theseparation between the footholds, which is shown at about 7 inches, canalso vary. To make transport of the cycle easier, the support pegs maybe made to fold upward, so that they do not protrude outward, therebypermitting the vehicle to lie flat. The design of a foothold, and theway in which it attaches to the fork, and the way by which it isadjusted to the rider's foot, and the way by which it can be adjusted tothe length of the rider's leg, can all be varied as long as the footholdfulfills the purpose intended, as described herein.

It should be noted that a most advantageous method of operating anactuator for the brake 28 may be that which is performed by the rider'sfeet. As illustrated in FIG. 7, when the rearward part of the foot isused to support the weight of the leg—the support peg 36 of the footholdbeing placed under the heel or arch for instance—the forward part of thefoot is able still to rotate up or down. This action could be used tocontrol the actuator for the brake, provided that the task does notinterfere with the general operation to the vehicle. For example, asshown in FIG. 7, a lever placed above the foot 38, which is operated bythe upward pivoting of the rider's foot, or a lever placed below thefoot 40, which is operated by the downward pivoting of the rider's foot,could be used to actuate the rear brake 28. Alternatively, either levercould be used to control a brake (not shown) which is operative on thefront wheel. It should be noted that the lever on one foothold may beoperated independently of the corresponding one which is on the other.It should also be noted, that on each foothold, one lever or the othercould operate a brake, the other being replaced by a fixed peg which iscapable of resisting upward or downward force, whichever the case.Furthermore, if peg 38 is made fixed it would then be an accessorycontact means since the muscles of the rider's foot and or leg wouldneed to be contracted in order to engage it.

Operation of the Cycle

When first observing the inactive cycle, it may be assumed that it issteered by the footholds with the rider's feet, because without ahandlebar there would appear to be no other way. Yet when observed inoperation, aside from the rider's poling strokes which are obviouslypropelling it onward, there is no noticeable action that indicates therider is in control of the vehicle. In fact, even when riding the cycle,as this inventor as done, it is not apparent how it works. It is clear,however, that cycle and rider lean into turns together, as one rigidmass; but whether this lean is an initiation of action, or a response toanother action, cannot be discerned. The lean of rider and cycle, andthe pivot of the cycle's forward wheel appear to be simultaneous acts.

As the steering wheel pivots one way or the other, the rider's legs seemto remain more or less fixed in position with respect to each other,like they would in a normal sitting position as illustrated in FIG. 5.However, without appearing to do so, the shanks of the legs pivot at theknees, with the ankles adding to the movement, and thereby togetherallow the feet to follow to rotating movements of the steering fork. Thefeet move more or less in unison, to the left or to the right, using thefootholds as guides to follow the same pivoting motion of the steeringwheel. The swiveling of the feet is necessary in order to avoid strikingthe spokes. From the perspective of the rider the actions of the legsand feet are spontaneous; and again, it is not clear whether the feetare following the action, causing it, or leading it.

Consider a rider propelling the cycle down a straight bike path at amoderate speed (say four to five feet per second). When the vehicle isfelt to be falling to the left-hand side, the rider intuitively steersto the left to keep their balance—that is the rider guides the vehiclein a circular arc, the center of which is situated at the left-hand sideof the vehicle. Centrifugal force due to the circular motion of thevehicle and rider now balances the tendency of the vehicle to overturn;in fact, the rider automatically steers the vehicle in a circle of sucha radius that the centrifugal force slightly overbalances the tendencyto overturn, and the vehicle again regains its vertical position. Therider now steers for a short interval of time exactly in a straightline. But probably the vertical position has been slightly overshot, andthe vehicle falls slightly to the right-hand side of the vehicle. Therider now unconsciously steers to this side, again in a circle nowhaving its center to the right-hand side—and so forth. If the track ofthe vehicle is examined it will be found to be, not a straight line, buta long sinuous curve.

The above illustration of riding a cycle was actually provided byArchibald Sharp and refers to a tradition bicycle, but was used herebecause it applies as well to the invention. Sharp's two-wheeler isequipped with a handlebar, and when Sharps refers to “steers” it meansof course “with” the handlebar. In the invention, steering the cycle isjust as intuitive and automatic, except an apparent explanation is notas handy. Obviously the rider's feet, which engage the footholds, play apart as speculated herein; however other forces are at play too. WhenSharp refers to centrifugal force, it is in the context of keeping thebicycle upright; the mass which the force pushes against in order toprevent the vehicle from falling being mostly that of the rider. Theinfluence of other forces, if any, is not mentioned.

In the invention, the cycle operates by the same principle as thebicycle in Sharp's example, although in comparison, its control isdependent more on the cycle's configuration and the dynamics involved,instead of on the rider's intervention though the use of the handlebars.A key factor in the operation is the torque that is created about thesteering axis, which is a consequence of the geometry of the vehicle'slayout and its effect on the vehicle's behavior in the presence of theforce-of-gravity. If the steering wheel is free to orient itself, thetorque will tend to pivot the steering wheel about the steering axis inthe direction of this twisting force. In Sharp's example, the torquethat is generated about the steering axis is not considered to benecessary to its operation; and its effect is overpowered by the rider'suse of the handlebars, which dominate its handling.

When the cycle is being ridden—fast enough to where the poles would havelittle effect on its steering and balance—it is usually tipped, if onlyslightly, to either side of its longitudinal axis. As a consequence, twovariables associated with the dynamics of controlling the cycle—the tiltangle and the steering angle—are continually in play. At any instant therate at which the vehicle turns is controlled by a combination of thesetwo angles. The tilt angle is defined herein as the inclination of thevehicle plane—defined by the rear wheel point-of-contact with the groundcontact and the steering axis—from its mid-plane or vertical position.The steering angle is defined as the deviation of the forward memberfrom its straight-ahead or mid position. Both angles have a left orright polarity, which is with respect to their mid or middle positions.It should be noted that when the vehicle is upright—the rear wheel beingvertical—and both wheels are perfectly aligned, the tilt angle and thesteering angle are zero; and therefore no torque is present about thesteering axis.

As the tilt angle and the steering angle vary—that is the cycle is notin a perfectly vertical position—torque will develop about the steeringaxis. The tilt angle is at the rider's command, which the rider controlsby leaning sideways. To produce a desired steering angle, if no accountis taken of the rider's feet on the footholds, a certain amount oftorque must be generated about the steering axis in order to pivot thesteering wheel. Initially the torque will be clockwise when the vehicleis tilting to the right of the longitudinal axis and counter-clockwisewhen tilting to the left. And as the steering wheel pivots, the weightof the rider's lower legs, which is supported by the foothold, pivotswith it. It is at this point, after which the vehicle has responded tothe rider's initial tilt command, and the rider is to one side of thevehicle's longitudinal axis, the explanation of the vehicle's behaviorin responds to the rider's handling becomes less clear.

In general, when the rider leans their torso sideways—and possiblytogether with other forces—the steering wheel tends to follow. It may bethat the pivoting of the steering wheel is also being influenceddirectly by the rider's feet via their engagement with the footholds.Although it is difficult to determine the actual scope of theirinfluence, it is the opinion of the inventor that the steering of thecycle is not dominated by the use of the footholds. It seems that therider relies to a greater extent on the tilting of the vehicle, and theresulting presents of torque about the steering axis; and the use thefootholds is more to augment or damp the effects of this torque, as maybe needed. It may be helpful to note, during actual riding conditions,the steering angle would most likely fall within a range of plus orminus 10-40 degrees across the vehicle's speed range, the lower figurebeing for the fastest speed, the upper figure being for the slowest,with plus or minus 20 degree being the nominal range during typicalriding situations. The corresponding tilt angles for this typical ridingsituation would likely be much less.

When the torque is in balance with those forces tending to counter-twistthe steering wheel, as explained herein, rider and cycle will be inequilibrium and the cycle will be turning at a constant radius. The tiltangle and steering angle will also be constant, and the force that therider is applying to each foothold will be steady. If any of a number ofvariable changes, including the cycle's velocity, the tilt angle, or theforce that is being applied to the footholds, the cycle will enter astate of transition until a new state of equilibrium is reached. Therider is able to intuitively control this process. As a practicalmatter, it should be noted that it is not likely that a rider wouldattempt to vary the steering and tilt angles in opposite directionswithout upsetting the vehicle, excluding the well-known phenomenon ofcounter-steering, during which such a condition could momentarily takeplace. It is not known to what extent, if any, counter-steering plays inthe invention, although if it is a factor, it would be dealt withintuitively since the rider of the model had no awareness of it.

Referring back to Sharp's illustration of riding a bicycle, this processof balancing works until the vehicle's velocity falls below a certainspeed, at which time the centrifugal force caused by the circular motionof the vehicle and rider becomes insufficient. When this happens, therider finds it difficult to maintain balance, and may choose to speedup, or instead, attempt to stay balanced by swinging the handlebar inthe opposite direction from the lean, rapidly countering the lean—thenback the other way, and so on. This action causes the center-of-mass ofrider and vehicle to rise up, and to oscillate back and forth about thelongitudinal axis in sync with the swinging handlebar. However, as thebicycle's speed drops further, the rider is no longer able to maintainbalance. Centrifugal force is no longer a factor, and the rider isforced to extend a leg to prevent the vehicle from falling to theground.

This is not the case with the invention. First of all, the vehicle has ashortened wheelbase, more on the order of a scooter, which allows it todevelop nearly twice the centrifugal force for a given speed and turningradius versus a traditional bicycle; and therefore the vehicle cannaturally maintain balance at much slower speed. Nevertheless, there isa point where a lack of centrifugal force exists due to insufficientvelocity, and the vehicle starts to become difficult to balance. It isat this point that the use of the poles—the manner in which they aremanipulated—that fulfills the invention's goal of slow-speed operation.The poles can be used to maintain the vehicle in a near-verticalposition, which allows the cycle to travel in more or less a straightcourse. This maneuver is possible because the rider can sense when thecenter-of-mass of rider and vehicle is over the longitudinal axis, andinstantaneously correct for the smallest deviation to either side, usingthat pole on the side to which the vehicle is tending to lean, topush—that is supplying sufficient lateral force—and thereby rebalancethe vehicle and rider. With the poles the rider can actually stayupright right down to zero velocity without having to lower a foot tothe ground.

Furthermore, during operation of the cycle at slow speeds, the poles canbe useful in turning. For instance, a pole can be employed to preventthe vehicle from tilting into a turn further than intended, and this canbe done in a manner that at the same time provides some forward thrustthat propels the cycle onward. Or, when preparing to turn to the otherside, a lateral shove with the pole can raise the rider'scenter-of-gravity and help push the rider over to that side of thevehicle's longitudinal axis. However it may be noticed, especially atvery slow speeds where the rider may not be able to preserve equilibriumwithout the use of the poles the cycle will tend to keep turning sharperinto the turn causing the rider to fall unless the pole is extendedoutward. It is not possible to prevent this from happening by using thefootholds alone. When this occurs the rider must employ the pole toraise their center-of-mass by pushing laterally on the pole, or instead,possibly just lean on the pole to maintain the present height of theirmass, and thereby prevent the reduction of the turning radius.

Generating Torque

Torque is in fact a moment, and as such is the product of force actingon a lever arm. As noted, torque can occur about the steering axiswhenever the rider is leaning sideways, which causes the tilt angle andthe steering angle to be greater than zero. As further noted herein,there are two components of said torque: one being a function of themass which bears on the cycle's forward member, the other being afunction of a portion of that mass. Each component of said torque has alever arm which is associated with specific variables of the cycle'sdesign that are related to the setup of the vehicle's forward member.The generation of torque about the steering axis, therefore, can beviewed as a process that involves two separate methods.

A first method, which relies on the fundamental configuration of thetraditional bicycle, is based on the trail of the vehicle's forwardwheel, or more precisely its mechanical trail—defined as the closestdistance between: the point-of-contact of the steering wheel with theground, and the steering axis. The trail, in effect, is the lever arm ofthe moment in said first method, and as such operates about the steeringaxis. The trail is a result of the rearward slant of the steering tube,which causes the axle of the steering wheel to move forward with respectto the rear-wheel axle. As said slant increases, the steering wheel'spoint-of-contact with the ground moves rearward with respect to thatpoint at which the steering axis intersects the ground, and thatincreases the length of the trail.

It is important to realize that said lever arm is in the plane of thesteering wheel and has no affect when the steering wheel is aligned withthe vehicle plane, that is when the front and rear wheel contact pointswith the ground are in the plane that includes the steering axis. Saidlever arm comes into play whenever the steering wheel deviates from itsstraight-ahead or middle position. When that occurs the steering wheelpoint-of-contact with the ground moves away from the vehicle plane. Thiscauses the support force—that is the force which pushes verticallyupward on said point-of-contact in reaction to the weight on thewheel—to form a component, which is perpendicular to the plane of thewheel. Said component force acts on the lever arm. The resulting momentcan produce torque that tends to pivot the wheel in the direction inwhich the vehicle tilts.

In a second method, the generation of torque is based on that distancefrom which the center-of-mass—of that mass which rotates about thesteering axis—is spaced, or offset, forward of the steering axis.Included in said mass is the front wheel and fork, and in the case ofthe preferred embodiment, the footholds and that portion of the mass ofthe rider's legs and feet that is supported by the footholds. The weightof said mass can produce a moment about the steering axis, its lever armin effect being equal to the length of the perpendicular distancebetween the steering axis and said center-of-mass. It is important tounderstand, that when the vehicle is upright with the tilt angle nearzero, and the steering wheel is at its middle position with the steeringangle near zero, the force-of-gravity from a side-to-side or a lateralperspective is parallel to the steering axis, and therefore its effecton said mass is directed downward in the plane of the steering wheel;and hence no torque is being generated from said second method. Wheneverthe vehicle tilts—the tilt angle being greater than zero—the affect ofthe weight of said mass creates a downward force that is not in theplane of the steering wheel. This force has a component that isperpendicular to the plane of the steering wheel; and said component canact on said lever arm and produce torque which tends to pivot thesteering wheel about the steering axis.

In the case of the preferred embodiment, the front fork is straight,that is the legs of the fork are aligned with the steering axis.Therefore the mass of the fork and wheel is symmetrically distributed inthe plane of the wheel with respect to the steering axis; andconsequently, this mass is not a significant factor in the production oftorque. Hence, it is the placement of the footholds and the weight whichthey support that is responsible for the generation of torque in thesecond method. According to the invention, in the preferred embodimentof the cycle, the position of the footholds is a critical factor in thesteering and balancing of the vehicle. In the case of the cycle with itsfootholds attached to the rearward member, referred to earlier, in orderto generate torque by said second method, the front wheel could beoffset by curving the fork legs forward, for instance, or some other waywhich places weight forward of the steering axis.

It should be noted that in a bicycle—where the term “offset” is definedas the shortest distance between the steering axis and the axle of thesteering wheel—the front axle is generally forward of the steering axis,which shifts some of the weight of the fork and wheel forward of thesteering axis. Excluding that weight that a rider might contribute byleaning on the handlebar, as would be the case when steering withouthands, only a small amount of torque is generated about the steeringaxis due to said offset. Although in the case of the preferredembodiment of the cycle said offset is zero, due to the horizontalposition of the rider's thighs, which extend forward over the top of thesteering wheel, the mass which is supported by the footholds can besignificantly greater than the combined mass of the wheel and fork, itbeing approximately fifteen percent of a rider's total body weight; andtherefore a significant amount of torque can be generated.

According to the invention, the center-of-mass of that weight which issupported by the footholds (when they are attached to the forwardmember) must be located forward of the steering axis. When this is true,said two methods of torque generation will tend to produce their torquein the same direction around the steering axis. Although the torquewhich is produced by each method may be associated with theforce-of-gravity, it may also be true that the directions of the forceswhich act on the lever arm in each of said two methods are directed fromopposite sides of the steering wheel. In the first method the force isrearward of the steering axis; and in the second method it is forward ofthe steering axis; the two lever arms being 180 degrees apart inrelation to the steering axis.

If this be the case, then the force that acts on each said lever armoriginates from opposite directions and therefore cannot be the sameforce in each case. In said first method, the force pushes verticallyupward at the front wheel's point-of-contact with the ground—being thereaction to the force-of-gravity—and supports the total mass carried bythe wheel. In said second method, the force pushes verticallydownward—being the force-of-gravity—and bears on that mass which pivotswith the forward member, which includes said offset mass. Therefore, itcan be concluded that said first moment and said second moment areindependent actions. Since the one does not depend on the other, eitherone can be adjusted or modified without affecting the other.

The rider can generate said torque in either direction—clockwise orcounterclockwise about the steering axis—by causing the vehicle to tiltlaterally to one side or the other with respect to the vehicleslongitudinal axis. Therefore, to change the direction of the torque, andhence the direction in which the steering wheel is tending toward—eitherto the left or to the right of the steering wheel's mid position—theweight of the rider's body must first move to that side of the vehicle'slongitudinal axis. In order for this to happen the rider'scenter-of-mass must be raised up on the one side in order for it tocross over to the other side of the vehicle's longitudinal axis, whereit would then lower as the tilt angle increases on that side of thevehicle. This may require the rider's use of the footholds to createopposing torque, that is, damp that torque which is being currentlygenerated by said two methods; but whatever that action is that therider performs, it is apparent that it is done intuitively. At slowspeeds the poles can also be used to help raise the rider, as disclosedherein.

Controlling Torque

It is important to realize that in the invention there are twocenter-of-masses (COM) that are associated with the operation of thecycle. A first one, which is commonly associated with the bicycle, isthe COM for the entire system, which includes the mass of the vehicle,rider, and poles. This COM is located slightly forward of, and above,the saddle. When the cycle is turning, centrifugal force develops normalto the direction of travel—that is outward along the radius of theturn—and in effect pushes against this COM to counter theforce-of-gravity, which is tending to tip the vehicle towards the centerof the turn. The force-of-gravity and the centrifugal force tend torotate the cycle in opposite directions about the longitudinal axis.

A second COM is that one that is related to the mass that pivots withthe forward member and is associated with the steering axis. Aspreviously discussed, the mass supported by the footholds can berelatively large due to the weight of the rider's lower legs; andtherefore this second COM can be a significant factor in the handling ofthe cycle. In the modern bicycle, however, the COM of that mass whichpivots with the front fork is not regarded as a significant factor inthe steering and balancing of the vehicle. Compared to the effect thatthat centrifugal force which is being generated by the moving vehiclehas on said first COD, the effect that that centrifugal force can haveon the second COM, and how it might influence the balancing and steeringof a tradition bicycle, is generally ignored.

It is of interest to note, in Archibald Sharp's analytical explanationon riding a traditional bicycle while steering without hands—where it isassumed that the tilt angle is small, and the steering angle is alsosmall and constant, and no account is taken of the gyroscopic action ofthe wheel—there is no mention of centrifugal force. Sharp contends thatit is centripetal force that is the primary force that produces themoment that opposes, that is balances, the other two fore mentionedmoments—those associated with said first and said second methods oftorque generation about the steering axis. Sharp believes that saidcentripetal force acts tangential to the steering axis at the steeringwheel's point-of-contact with the ground, its lever arm being the lengthof the steering wheel's mechanical trail.

It is of interest to observe the affect trail has on the operation ofthe cycle in the invention. In an experiment conducted by the inventor,said model was modified so that its trail could be adjusted all the waydown to zero. The model was tested as the trail was reduced byincrements of twenty five percent; and as expected, its handling gotprogressively pooper; but surprisingly, even when the trail was adjustedto zero, the model could still be easily controlled. It is interestingto note that when the vehicle was being ridden without any trail,according to Sharp, said first method of torque generation, and saidopposing moment due to centripetal force, would not have been operative,since both moments require the trail as their lever arm. If this becorrect, then the presence of torque about the steering axis, if indeedit did exist, could have only been due to the effect of said secondmethod.

Then in this case, in order to balance that torque which is beingproduced by said second method during a constant-radius turn forinstance, or when vary the radius of the turn, some force other thancentripetal force would have had to been involved. It would bereasonable to infer that that force could be either: centrifugal forceacting on said first COM, or on said second COM, or to some degree onboth; a countering twist about the steering axis that can create adamping effect, that is produced by the action of the rider's feet onthe footholds; or some combination of the two. It may be that saidsecond COM is too close to the steering axis, or and the vehicle's speedrange is too slow, for said second method to be affected significantlyby centrifugal force.

On the other hand, given that the cycle has some amount of trail, saidcentripetal force may be the primary force which can counter the torquethat is present about the steering axis, as Sharp suggests. On thesubject of no-hands steering in a traditional bicycle, Carlos Bourlet's,whose opinion was highly regarded in an era when these topics werestudied at length, says that it would not be possible to ride a bicyclein which the steering axis cuts the ground at the point-of-contact ofthe front wheel—in other words a cycle with no trail. Taking this intoaccount, one would be inclined to believe then, given the results of theexperiment, the difference is a result of actions by the rider's feet onthe footholds; or in other words, the cycle in the preferred embodimentworks due to the subtle control that the rider is able to exert on thefootholds.

The question of steering and balancing a two-tandem vehicle hashistorically been regarded as complicated and especially confusing whenno-hands riding is involved. In Sharp's opinion, a rider attempting tosteer without hands by varying the tilt angle, that is balance thetorque about the steering axis by adjusting the lean or lateral positionof their torso, probably would not be quick enough to preserve theequilibrium of the vehicle. But this is not the case when riding themodel of the preferred embodiment, which has been proven to be easilycontrolled. Hence, since the only substantial difference between Sharp'shypothetical example and said model is that in the model the torqueabout the steering axis can be influenced by the use of the footholds,one may conclude—taking in Sharp's opinion—that indeed the weight andsubtle actions of the rider's feet on the footholds are in fact makingthe difference. It should be noted that in Sharp's example, the use ofcounter-steering would not have been possible since the handlebar wasnot being used. It is not known whether or not counter-steering is afactor in the steering of the cycle of the invention, although it wouldbe possible to perform by the rider's use of footholds.

Sharp's analysis relates to a tradition bicycle where the only massincluded in said second COM is that of the steering fork, front wheel,and the handlebar. And even though said COM is forward of the steeringaxis due to the offset caused by the bending of the fork legs, Sharpdoes not consider that centrifugal force could act on this mass tocounter that torque that tends to pivot the front wheel about thesteering axis. In the preferred embodiment of the invention, althoughthe fork is straight, said second COM can be significantly shiftedforward due to the placement of footholds. Therefore, the centrifugalforce which can act on it may be a significant factor in pushing thesteering wheel back towards its middle position, assuming that therider's lower limbs cooperate. If this is the case, it should be notedthat this action and its effect would seem to be the similar to that ofcentrifugal force acting on the said first COM in preventing the cyclefrom falling to the side.

It may be noticed that offset is little mentioned in bicycle science. Inthe earliest bicycle designs, the steering forks were straight—there wasno offset. Then with the advent of the safety bicycle—the moderntwo-wheeler—and thoughout the twentieth century, offset was virtuallypart of every design: the legs the front fork being curved forward toproduce it. It may be noticed that in all the references cited—Sharp'sClassic Treatise, Wilson's Bicycling Science, Bryant's patent, andPapadopoulos' chapter in the most recent addition of BicyclingScience—the topic of offset is hardly touched upon, although in mostcases a great deal of discussion is devoted to the topic of trail. BothSharp and Bryant point it out in their analysis but then fail to discussit. Papadopoulos simply states “The line of the steering axis commonlypasses below the front axle, that is, the fork is bent forward.”

It is important to realize that offset moves the steering wheel'spoint-of-contact with the ground forward, in the opposite direction ofthe trail; hence, for a given slant of the steering tube the trail willdecrease as the offset increases. The only real purpose that offsetprovides would appear to be that of moving said second COD furtherforward of the steering axis. This is not necessary in the preferredembodiment of the cycle, given that that objective can be betteraccomplished by the placement of the footholds. Experiments wereconducted on the model of the preferred embodiment where the steeringfork was bent forward to produce vary degrees of offset. In general, theeffect of vary amounts of offset was not significant, and no positiveadvantage could be discerned. The best overall performance seemed to beproduced with no offset. Therefore, in a preferred embodiment, accordingto the invention, the cycle has a straight steering fork with no offset.

Other Factors

Up to this point in the discussion, the assertion has been made that thecycle referred to in the invention is steered to some extent by twoindependent moments, which can act together to produce sufficient torqueabout the steering axis that can cause the steering wheel to pivot. Theinfluence on said moments of that torque which can be produced by therider's lower legs via the footholds has not been taken into account,although it was speculated that the effect of such direct action couldbe to augment or damp the effects of said two moments. It should benoted that there is also a gyroscopic aspect—known to those in the fieldof bicycle design and cited by Jim Papadopoulos in the third edition ofBicycling Science—which may be a factor in the steering of said cycle;wherein, the angular momentum that is produce by the spinning motion ofthe cycle's steering wheel urges the wheel to pivot toward the side towhich the cycle is being tipped. Thus, the effect of this gyroscopicaction—known as precession—is to reinforce the said moments, that is addto the torque that is being generated by said first and second methods.

Furthermore, the angular momentum of the steering wheel is proportionalto the square of the cycle's velocity. Therefore, the effect ofprecession can vary during the operation of the cycle, depending on itsspeed. To what extent precession may influence the handling of the cyclehas not been determined. Whatever that extent may be, at normal speedsthe effect if any can be interpreted as manageable and helpful based onthe model's general performance. It may be that variations in torquethat are caused by precession are intuitively compensated for by theactions produced by the rider's feet on the footholds. It should benoted, however, that a sudden change in torque may cause handlingproblems at higher speeds that could cause a destabilizing of the cycle,where the steering wheel could quickly turn inward during a turn,resulting in an upset.

In another aspect pertaining to steering, it was noted that the steeringwheel can also pivot when lateral force is applied to the rearwardmember at the steering tube. This can be demonstrated when steering thecycle in its walking mode: where the dismounted rider walks alongsidethe cycle pushing it forward with their hand griping the saddle, andtwists the saddle thereby causing the steering wheel to pivot. It isalso possible to use this method while the cycle is being ridden;however, as in the case of the walking mode, the rear member of thecycle needs to be close to its near-vertical upright position for it towork effectively. Then, if the rider should twist their one thigh aboutthe buttock, thereby applying lateral force with their inner thigh toone of the accessory contacts attached to the side of the steering tube,the steering wheel will pivot in the direction of the applied force.Although it may be difficult to discern, this action may be useful incausing the steering wheel to pivot from one side of the longitudinalaxis to the other, and thereby help the rider to change directionfaster. This action demonstrates that body English can be a factor inthe control of the cycle. It should be noted that this effect is afunction of the length of the cycle's trail.

It is important to realize that the speed range over which a two-wheeltandem vehicle operates is a major factor in its handlingcharacteristics. These vehicles rely to varying degrees on the presentsof centrifugal force, and its counterpart centripetal force, in theiroperation. These forces are a function of the vehicles speed, and areproportional to the square of its velocity. Thus the design of aparticular type, or category, of two-wheel tandem vehicle is based inlarge part on its speed range. Within a category, the speed range can beviewed as a design parameter—that is the speed at which the vehicle isintended to be operated; or alternatively, it can be viewed as alimiting factor of, or inherent to, the design itself. For example, abicycle can be designed for slower speeds, like a “cruiser” type, or forhigh speeds, like a “track” bike; but, it cannot be made to operate atvery slow speed—like a scooter can, for instance. Likewise, a scootercan be designed to operate in varying speed ranges; but, no scooterwould be stable at the speeds that the motorcycle operates. It isobvious that a bicycle, a scooter and a motorcycle are distinct vehiclesin spite of their shared two-wheel tandem configuration.

The cycle in the invention is a distinct vehicle too. It should not beconfused with other two-wheel tandem vehicles, like the bicycle forinstance. In general said stability and balance are superior in abicycle compared to that in the cycle of the invention; and therefore, abicycle's handling characteristics can accommodate a much greater rangeof operating speed. In the invention, the attainment of a slow-speedoperating capability is a major achievement that is conducive, if notnecessary, for the particular means of propulsion—the use of handheldpoles. The cycle's speed range is directly dependent on themovements—thus the muscles—of the rider's arms and shoulders. And likethe scooter, on a level riding surfaces, the cycle cannot exceed thespeed at which a rider can thrust it forward. Although pushing with thepoles at a slower pace allows a rider to conserve energy when desired,exercise of the rider's upper body is an important feature of theinvention.

As noted with respect to the generation of torque, said first and secondmethods are not depended on each other. Therefore, if either such methodhas a purpose other than torque generation, it would be advantageous tothe cycle's design to consider it separately, and to determine itsrelative important to the vehicle's overall performance and proceedaccordingly. Thus, in this regard, the primary purpose of the trail,which is associated with said first method, is to improve the basichandling of the vehicle, as is well known to those skilled in the art ofbicycle design. Generally the same principles and consideration thatapply to the bicycle would apply to the vehicle in the invention. In theconstruction of the model, prior to giving consideration to said secondmethod of torque generation, the trail was optimized to produce thegreatest benefit to the handling and stability of the vehicle based on:its operating speed range, wheelbase and expected mass of the rider.This was accomplished by tuning the length of the trail while therider's weight was being supported, as near as possible, in the sameratio between forward and rearward members as it would be in thepreferred embodiment.

With the variables associated with said first method established, saidsecond method can then be dealt with, the goal being to optimize saidsecond moment to produce the best steering characteristics possiblebased on the given torque generated by said first method. During theperiod of experimentation prior to the development of the preferredembodiment, several other attempts were made to ride varying designs oftwo-wheel tandem vehicles without handlebars. One of the most difficultproblems to overcome was the reconciliation of the dual function of thefootholds. On the one hand footholds were critical in stabilizing therider on the vehicle; and on the other, they were a critical part of thesteering process—seemingly incompatible objectives. The determination oftheir best location on the vehicle, which resulted in the effectivenessand the ease of their use by the rider, in fulfillment of bothfunctions, was a major achievement. It is important to realize thattheir use, both as a means to pivot the steering wheel and to supportthe rider, should not restrict the natural tendency of the steeringwheel to pivot in response to the tilt of the vehicle by unintentionallydisturbing the presents of torque about the steering axis.

According to the invention, the optimization of the position andlocation of the rider's legs and feet on the cycle can be a criticalfactor in the steering and balancing of the vehicle. In this regard, theplacement of the footholds with respect to the steering axis is the mostimportant consideration in the case of the preferred embodiment of thecycle. It should be noted that whereas the generation of torque in saidsecond method is concerned with the location and weight of the rider'slegs and feet, the ease and control of the movement of the steeringwheel by the rider's use of the foothold is more concern with theposition of the legs and feet. Therefore, the location of the footholdsmust be such that the handling characteristic of the vehicle areoptimized based on the mass and size of a given rider. As a practicalmatter the exact position of the footholds could be adjustable and setup at the time that the vehicle is acquired. Experiments using the modelof the preferred embodiment showed that for a given rider there exists asweet spot for the location of the footholds where the vehicle performedthe best. If the position of the rider's feet were either move too farforward or rearward from this location the vehicle becomes unrideable.

Propulsion

Poling is feasible in a two-wheel tandem vehicle because the force thatis necessary to thrust the vehicle forward can be applied in a directionthat is parallel to the vehicle's inherently stable longitudinal axis;and, it can be done in a manner that does not produce a destabilizingmoment—that is torsion about the rider—that cannot be countered by therider's actions. To illustrate: In the simplest of propulsion actions,the rider commences by extending both arms forward; and with pole tipspointed straight down, plants them on the road; and thenimmediately—starting the power stroke—applies downward pressure on thetips to keep them in place, while at the same time, pulling thevertically held poles rearward by bending the elbows. The vehicle isthus trusted forward for that period of time during which it takes tocause the elbows to bend so that the pole handles end up even with thechest. The rider then completes the stroke by lifting the poles; and thearms are again extended forward to start the next stroke.

Note, that during the power stroke, with pole tips planted equaldistance on either side of the longitudinal axis, when the rider appliesequal pulling force to each pole, the torque that is produced by onepole is canceled by that which is produced by the other. The clockwisemoment about the rider, which is caused by the rider pulling theleft-side pole, is cancelled by the counterclockwise moment caused bythe right-hand pole. Therefore, the net force thrusting the vehicleforward is in line with the vehicle's longitudinal axis. Fortunately, itwas discovered that this degree of precision poling is not necessary inorder to maintain stability, as disclosed herein.

Poling where both poles are used in unison, like the “double pull”stroke cited above, can be varied to suit different purposes. The“double pull” for instance, is an ideal stroke for very slow speedswhere balancing is difficult, or not possible, without the effect of itsstabilizing nature. Another example is the “double push”, which is agood stroke for starting from a standstill, as illustrated here: Therider gets into position astride the stationary vehicle, with elbowsfully bent drawing the poles to the chest, and pole tips planted belowthe saddle adjacent to the outside of each foot. Then raising the feetto the footholds while balancing upright between the poles, the riderstarts the power stroke by rocking forward, rotating the upper body atthe hips, while applying that same downward pressure to the poles thatkeep the tips in place. And, as the shoulders pass forward of the poletips, the rider trusts the poles backward, partially unwinding theelbows to complete the rather short stroke. The poles are then rapidlylifted and moved forward to repeat the stroke, and so on, until thevehicle gains efficient momentum.

The force applied to any stroke, or elapsed time between successivestrokes, can be varied by the rider to suit conditions andcircumstances. A very rapid full power “double pull” stroke might beneeded for fast acceleration. Or in heavy pedestrian traffic, the samestroke could be used to move very slowly by applying minimum power butvery quick elapse time between strokes, thereby keeping the poles incontact with the road as long as possible. And again for example, underaggressive poling, the long and efficient “double pull-push” stroke,which combines the “double pull” and “double push” strokes, the onepicking up where the other left off, can be the best stroke for powerand speed; however with less aggressive poling it can also be a greatcruising stroke with a hypnotic rhythm. The trusting power of any one ofthese three “double” type strokes can be increased by either: extendingthe poles further forward at the start of the stroke by bending theupper body forward at the hips, or extending the poles further rearwardat the end of the stoke, or both.

Of major significance, with respect to “double” poling, it was foundthat the rider could vary, without apparent awareness, the amount offorce applied to one pole or the other to compensate for imbalancescaused by uneven poling, or shifts in the rider's position with respectto the vehicle, or variation of the riding surface. This previouslyunrealized effect seems to complement the two-wheeler effect ofcorrecting for tilt by turning the forward wheel in the direction of thetilt. The meaning of this important discovery is that poling can be morethan just the means of propulsion; it can also be an integral part of acomplex balance and stability system, with a feedback loop whichincludes the rider, vehicle, and poles that operate together to helpcontrol the vehicle's ride as it travels on.

The discussion so far has dealt with “double” poling, which ischaracterized by the use of both poles in unison. Another basic polingcategory is the “alternate” where the poles are alternately used backand forth, first poling on the one side, then the other, there being aresemblance between the actions of the poles and those of a walker'slegs. The “alternate pull”, and the “alternate push”, and the “alternatepull-push” are the counterparts to their respectively named stroke inthe “double” poling category; and the comments previously cited thatpertain to the “double” strokes apply to their “alternate” strokecounterpart, except for one important difference: Unlike “double”poling, with “alternate” poling the torque produced by the one pole doesnot cancel out that which is produced by the other.

When the rider propels the vehicle forward, the force which is appliedto the poles is in a direction that is parallel to the vehicle'slongitudinal axis; and hence, most of the power that is produced is inline with the direction of travel. But because the poling force isoffset from the axis itself—the pole tips are set on either side of theaxis separated by the width of the rider's shoulders—a potentiallydestabilizing moment is also produced. The thrust of a pole has atendency to produce motion, or torsion, about the rider's body—think ofa canoe twisting side-to-side when paddled. When poling on the vehicle'sright side, the force that the rider exerts on the pole to propel thevehicle forward will tend to twist the rider's body counterclockwise, orin the case of left side poling, clockwise.

This destabilizing moment can upset rider and vehicle if not counteredby an opposing action, such as an opposite force of equal magnitude asillustrate in the “double pull” example, where the moment produced bythe one pole is cancelled by that produced by the other. And indeed,this is true for the entire “double” poling category where right sideand left side poling actions are in unison; and consequently, theopposing moments that result tend to counteract each other. This is nottrue, however, for “alternate” poling. In this case every stroke must becountered by the rider to prevent the resulting moment from upsettingthe vehicle. The rider creates this counteraction by either leaning, orby turning the vehicle's forward wheel, or some combination of theseactions, or some other maneuver that works.

Whatever that opposing action is that the rider employs to counteractthe torque caused by an “alternate” stroke, it can be repeated forsuccessive strokes to form a continuous pattern or rhythm which therider may find interesting. For instance, the vehicle can be made tooscillate back and forth side-to-side, or the rider could sway or twistback and forth. Any of the various strokes in the “alternate” polingcategory can be used to “walk” the vehicle in this manner, provided thatthe rider produces a corresponding opposing action. That same feedbackloop which was referenced to the “double” poling category applies herefor “alternate” type strokes; whereby the rider intuitively balances thetorque caused by the “alternate” stroke with that generated by theopposing action.

It should be understood that the examples and embodiments describedherein are for illustrative purposes only and that various modificationsor changes in light thereof will be suggested to persons skilled in theart and are to be included within the spirit and purview of thisapplication and the scope of the appended claims.

1. A two-wheeled tandem vehicle propelled by a rider with poles alongthe ground comprising: two structural members, a forward structuralmember supported by a rotatably mounted front wheel, the forwardstructural member pivotally connected to a rearward structural membersupported by a rotatably mounted rear wheel, the front wheel pivotingabout a substantially vertical steering axis, the rear wheel alignedwith and following the front wheel, the steering axis and a point ofcontact with the ground of the rear wheel defining a plane; a saddlemounted to the rearward structural member and aligned in the plane;footholds mounted to one of the two structural members; and at least onepole; wherein the vehicle has no handlebars and the rider propels thevehicle with the at least one pole.
 2. The two-wheeled tandem vehicle ofclaim 1, wherein said vehicle further comprises at least one accessorycontact means mounted on at least one of said forward structural memberand said rearward structural member.
 3. The two-wheeled tandem vehicleof claim 1, wherein said footholds are mounted to said forwardstructural member disposed on each side of said front wheel andpositioned on said front structural member to support weight of therider's feet and legs forward of said steering axis.
 4. The two-wheeledtandem vehicle of claim 2, wherein said at least one accessory contactmeans is attached to said rearward structural member and is positionedon each side of said steering axis to contact the rider at the innerthigh.
 5. The two-wheeled tandem vehicle of claim 2, wherein said atleast one accessory contact means is attached to said rearwardstructural member and is positioned forward of said steering axisdisposed on each side of said plane to contact the rider at the innerknee.
 6. The two-wheeled tandem vehicle of claim 2, wherein said atleast one accessory contact means is created by elongating said saddle.7. The two-wheeled tandem vehicle of claim 1, wherein said footholds aremounted to said rearward structural member and disposed on each side ofsaid plane.
 8. The two-wheeled tandem vehicle of claim 7, furthercomprising a linkage connecting said footholds to said forwardstructural member by which said forward structural member can bepivoted.
 9. The two-wheeled tandem vehicle of claim 8, wherein saidfootholds pivot upward and downward and move reciprocatively relative toone another.
 10. The two-wheeled tandem vehicle of claim 1, wherein atleast one of said footholds comprises an upper peg and a lower peg. 11.The two-wheeled tandem vehicle of claim 1, wherein said vehicle furthercomprises a brake to arrest at least one of said rear wheel or saidfront wheel.
 12. The two-wheeled tandem vehicle of claim 11, wherein anactuator of the brake is a lever.
 13. The two-wheeled tandem vehicle ofclaim 11, wherein an actuator of said brake is a lever controlled by atleast one foot of the rider.
 14. The two-wheeled tandem vehicle of claim11, wherein at least one of said footholds comprises an upper peg and alower peg, and at least one upper peg is an actuator of said brake. 15.The two-wheeled tandem vehicle of claim 14, wherein at least one of saidupper peg and said lower peg is a lever, or part thereof.
 16. Thetwo-wheeled tandem vehicle of claim 11, wherein at least one of saidfootholds comprises an upper peg and a lower peg, and at least one lowerpeg is an actuator of said brake.
 17. The two-wheeled tandem vehicle ofclaim 16, wherein at least one of said upper peg and said lower peg is alever, or part thereof.
 18. The two-wheeled tandem vehicle of claim 7,wherein said forward structural member is configured to position acenter-of-mass forward of said steering axis.
 19. The two-wheeled tandemvehicle of claim 1, wherein said steering axis is inclined rearward withrespect to said plane.
 20. The two-wheeled tandem vehicle of claim 1,wherein said footholds are configured to resist force from at least onefoot of the rider, the force directed inward toward the other foothold.